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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

Will Field of View Change with the EPIC?

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Andrew Patterson

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I'm coming from the RED ONE with a smaller sensor. So if I'm shooting 5K Full Frame, will my Angle of View at say 18mm become wider than I am used to?

I am getting messed up on this because I have always associated Angle of View with Lens MM. Now I'm learning that 18mm on the RED ONE is The same as 21mm on the EPIC. This is my source: abelcine.com/fov

I'm also learning that at 18mm my FOV on the RED ONE goes from 63.2 Degrees to 71.4 Degrees on the EPIC. So you're picking up Angle as sensor increases? So in other words, I've always mistakenly associated my FOV in relation to the RED ONE sensor? And with many lenses there is more angle to offer?

Am I understanding this correctly?
 
Wow -- thank you, Gunleik! That was virtually immediate service!
 
Larger the sensor the greater the field of view. 16mm sensor is 2x more narrow then s35mm which is why a 25mm lens on the red one mx becomes a 50mm lens at 2k. Full frame is a bit larger than S35 so you will have an increase in the field of view. Field of view also relates to the mm of a lens, 50mm has a narrower field of view than a 25mm.

Hope this makes sense.
 
I understand the relationship between separate lenses and how increasing them narrows the field, I just didn't know the Field could change based on sensor size. For example, I assumed 18mm represented a cone of visibility protruding from the lens and that an 18mm meant you always got that FOV no matter what size the sensor as long as the lens was made for that sensor -- in other words, an 18mm lens designed for Micro 4/3 would give you the same FOV or Cone of Visibility as an 18mm Designed for APS-C, etc. So I was always associating Degree of Visibiliy with Focal Length when that is only half the equation along with Sensor Size.

So let me ask this -- sensor coverage can vary from lens to lens, but they are still considered equal focal lengths? For example, an APS-C 18-50mm vs an 18-50mm Full Frame will cover different amounts of the sensor. So their FOV is quite different even at identical Focal Lengths -- is this correct?
 
Alright, so EPIC's Full Frame mode -- it's not 36x24mm.
So why am I seeing that in screen grabs? What does Full Frame mean if not 36x24?
 
Got it -- Thank You, Matt.

So last question: does anyone refer to lenses by their Degree of Visibility instead of Focal Length? That just seems MUCH easier to comprehend!
 
Well, by Degree of Visibiliy, I just mean the cone angle the lens is viewing. I know the other factors will be different every time.

Leica Lists their Degree of Visibility in their Specs . . .
 
Depending on lens coverage the degree would theoretically change. A ff35 Canon lens would differ from a S35 lens as the ff would have a greater coverage area.
 
That is true -- I see the reason why it's Focal Length over Angle of View -- but now I know how to get the true FOV for each sensor.
 
Focal Length [mm] 18
Epic sensor Width [mm] 27.468
Epic sensor Height [mm] 14.58
Diagonal [mm] 31.0977077
Horizontal angle of view [degrees] 74.7251456
Vertical angle of view [degrees] 44.11826101
Diagonal angle of view [degrees] 81.68397223


subject distance [m] 1 horizontal size [m] 0.763
 
Matt Ryan said:
No, always by focal length.

Degree would be a weird thing to call out on set. "Give me a 54 degree lens."
Click to expand...

FWIW thats how the lenses on the Optex Excellence are marked, however 2/3 inch Video & s35 are assumed!
 
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